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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 60, Number 1
JKCSEZ 60(1)
February 20, 2016 

 
Title
Studies of Solvolyses of Biphenyl-4-carbonyl Chloride by Extended Grunwald-Winstein Equation

확장된 Gruwald-Winstein 식에 의한 Biphenyl-4-carbonyl chloride의 가용매분해 반응대한 연구
Author
Hojune Choi, Han Joong Koh, Kiyull Yang, In Sun Koo*

최호준, 고한중, 양기열, 구인선*
Keywords
Biphenyl-4-carbonyl chloride, extended Grunwald-Winstein 식, 해리성 SN2 반응 , Biphenyl-4-carbonyl chloride, Extended Grunwald-Winstein equation, Dissociative SN2 mechanism
Abstract
이성분 혼합 용매계인 MeOH-H2O, EtOH-H2O, acetone-H2O, TFE-H2O에서 biphenyl-4-carbonyl chloride (C6H5C6H4COCl, 1)의 가용매 분해반응을 25 oC에서 수행하였다. 이들 속도자료로부터 simple Gunwald-Winstein식을 사용하여 도시하였을 때 분산현상이 나타나는 것을 볼 수 있었다. 분산현상의 개선을 위해 친핵성도 NT 및 방향족 고리 변수 I가 포함된 extended Gruwald-Winstein 식을 사용하여 도시하였다. 본 연구에서 구한 l, m, h 값 및 비교적 작은 양의 ΔH‡값(15.3~16.1 kcal/mol)과 비교적 큰 음의 ΔS‡ 값(-17.2~-20.0 cal/mol·K)의 활성화 파라메타 값으로부터 biphenyl-4-carbonyl chloride의 가용매 분해반 응은 해리성 SN2반응 메카니즘으로 진행됨이 예상되었다.

The solvolysis rate constants of biphenyl-4-carbonyl chloride (C6H5C6H5COCl, 1) in 19 different solvents are well correlated with the extended Grunwald-Winstein equation, using the NT solvent nucleophilicity scale, YCl solvent ionizing scale, and I aromatic ring parameter with sensitivity values of 0.31±0.10, 0.46±0.05, and 0.96±0.20 for l, m, and h, respectively. These l, m, and h values can be considered to support a dissciative SN2 reaction pathway. This interpretation is further supported by the activation parameters, i.e., relatively small positive ΔH‡ (15.3~16.1 kcal/mol) values and large negative ΔS‡ (-17.2~-20.0 cal/mol·K) values.

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